CITRUS HEIGHTS (CBS13) – A Citrus Heights man is behind bars accused of gunning down his own son. A neighbor tells CBS13 the suspect knocked on his door and confessed to the crime, which he thinks may have been in self defense.

Officers say they responded to reports of a family disturbance and a shooting in a home on the 7600 block of Kensington Drive around 8:30 p.m. Friday. When police arrived, they found the victim dead inside the home. The man’s father, Peter Bruce Rexius, 62, remained on scene and surrendered.

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“We’re horrified by this,” said Richard Ott, as he choked up.

The images are still fresh in his mind.

“It’s not the human thing to do,” he said.

Ott was inside his home off Kensington Drive Friday night when his next door neighbor banged on his front door, begging for help.

“’Rick. I need your help. I just shot my son,’” said Ott.

Ott ran next door to find his neighbor’s son on the floor breathing his final breaths.

“His boy was laid out on the living room floor, no shirt, obvious chest wound right here in the sternum area,” said Ott.

Ott says the victim is 27-year-old Daniel Rexius. Daniel’s father, Peter Rexius, is now in jail accused of pulling the trigger.

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Ott says immediately following the shooting Peter was showing remorse, telling his son he was sorry as they waited for help to arrive.

“He was physically shaken, probably wishing he could turn back the hands of time,” said Ott.

Police say Peter and his son got into an argument that evening that led to the shooting.

“When I went into the house it was obvious they had been tussling. And to be honest with you, the boy is big. He was a tall young man and I think Pete may have feared for his life at the time,” said Ott.

Ott says the father and son had only been living at the home for a few months.

“I had heard a few arguments, here and there — once in a while,” said Ott.

This time it was a fight that police say went too far, giving this neighbor a night he’ll never forget.

“Something terrible must have been going on in order to push somebody to that extreme,” said Ott.

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Peter was booked into the Sacramento Main Jail for murder and is being held without bail. He is scheduled to appear in court on July 23 at 1:30 p.m. He turned down our request for an interview.

Peter Rexius is accused of shooting and killing his son. (credit: Citrus Heights Police Dept.)

Peter Rexius is accused of shooting and killing his son. (credit: Citrus Heights Police Dept.)